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How to Choose a Trim Size: A Guide to Standard Book Sizes

Written by MasterClass

Last updated: Oct 2, 2020 • 3 min read

Books may come in one general shape, but they certainly come in a variety of sizes. The size of a book is discussed in terms of trim size. Publishers determine trim size based on a variety of factors, including economic considerations and the industry standards for certain types of books. For a publisher, it might make sense to publish one novel as large hardback book with an elegant dust jacket, while publishing another as a smaller mass market paperback meant to be sold in airports and grocery stores. Whether you are hoping to sell your book to a publisher or want to self-publish it on your own, the trim size of your book is important to consider as you plan your book’s layout and select paper stock.



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What Does Trim Size Mean?

In publishing parlance, trim size describes the height and width of the pages of a book. The trim size of a book has many ramifications for book design and layout. A larger page size can fit more words; the more words per page, the fewer pages overall. Paper stock and binding also contribute to the overall weight and size of a book.

What trim size a book is assigned depends on economic as well as aesthetic factors. For example, mass market books (the kind of paperback books you might see in the grocery store or airport) are a standard trim size of 4.25 x 6.87”, while trade paperbacks (the kind you’d typically find in a bookstore) can range from 5 x 8” to 8 x 10”.

3 Things to Consider When Choosing a Trim Size

There are few hard and fast rules when it comes to trim size, but there are a number of conventions. Here are three rules of thumb to keep on hand when choosing a trim size:

  1. Understand industry standards. While trade paperbacks (a broad category of fiction and nonfiction books) come in several different trim sizes, comics and mass market paperback books tend to adhere to a single industry-wide standard. At the same time, manuals, workbooks, and art books follow their own standards. Know the standards for your genre of writing.
  2. Be mindful of aesthetic implications. If you are self-publishing a novel using a print-on-demand service, trim size is one of the many factors you’ll need to consider. Say you’ve decided to publish a novel in a trade paperback size. The trim size you settle on will determine not just the height and width of your book, but the page count as well. For longer works, a larger trim size may keep the book from appearing like an unappealing brick. Conversely, shorter works may benefit from a smaller trim that will allow them to appear more substantial.
  3. Keep the reader in mind. One thing to keep in mind, especially if you’re working in a well-established genre like horror, sci-fi, or romance, is that it’s generally a good idea to adhere to the publishing conventions of your genre. Because readers tend to gravitate to what is familiar, you’ll probably want your book to at least outwardly appear similar to other books your readers are likely interested in.
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4 Standard Trim Sizes in Publishing

Trim sizes are typically dictated by genre. Within these genres, there tend to be a range of commonly accepted sizes. The only real exceptions are mass market paperbacks and comic books, which typically conform to an industry-wide standard. Here’s a list of common standards for popular genres:

  1. Mass market paperback books: This type of book is nearly always 4.25 x 6.87”.
  2. Comic books: Comics are nearly always 6.625 x 10.25”
  3. Trade paperbacks: Most fiction and general nonfiction books range from 5 x 8” to 6 x 9”. Shorter works, like novellas, are nearly always 5 x 8”. Hardbacks are most often 6 x 9”.
  4. Textbooks: Since they frequently include illustrations and diagrams, textbooks tend to range from 6 x 9” all the way up to 8.5 x 11.”

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